Optical system for measuring orientation with cubic wedge and mask

Abstract

The field of the invention is that of optical systems for detecting the posture of a mobile object in space. The system comprises an electro-optical fixed device of known orientation comprising a first point emission source, a telecentric emission/reception optic and a photosensitive matrix sensor. An assembly comprising an optical cubic wedge is disposed on the mobile object. The input face of the cubic wedge comprises a mask in the shape of a parallelogram, each side of the parallelogram comprising a geometric marking making it possible to identify it, the image of the mask projected on the photosensitive matrix sensor, by reflection on the faces of the cubic wedge, being the intersection of the projection of the mask and of the projection of its image inverted with respect to the centeR of the cubic wedge. Analysis of this image makes it possible to determine the orientation of the cubic wedge.

What is claimed is: 
     
       1. A system for detecting posture of a mobile object in space comprising:
 an electro-optical fixed device of known orientation comprising at least one first point emission source and a photosensitive matrix sensor; and 
 an assembly comprising an optical cubic wedge disposed on the mobile object, wherein:
 the electro-optical fixed device comprises a telecentric optic comprising a projection objective, a reception objective and a semi-reflecting optical element which are arranged in such a way that the at least one first point emission source is disposed at a focus of the projection objective by reflection or by transmission through the semi-reflecting optical element and that an image of the at least one first point emission source is disposed at a focus of the reception objective by transmission or by reflection through the semi-reflecting optical element; 
 an input face of the optical cubic wedge comprises a mask in a shape of a parallelogram, each side of the parallelogram comprising a geometric marking making it possible to identify each side, an image of the mask on the photosensitive matrix sensor, by reflection on the input face of the optical cubic wedge, being an intersection of a projection of the mask and of a projection of it's the image of the mask by the optical cubic wedge with respect to a centre of the optical cubic wedge. 
 
 
     
     
       2. The system for detecting the posture of the mobile object according to  claim 1 , wherein markings of the parallelogram are simple geometric shapes of small dimension with respect to dimensions of corresponding sides of the parallelogram and situated in a vicinity of ends of each side. 
     
     
       3. The system for detecting the posture of the mobile object according to  claim 2 , wherein the simple geometric shapes form lugs and/or notches. 
     
     
       4. The system for detecting the posture of the mobile object according to  claim 1 , wherein the at least one first point emission source or its image is disposed on an optical axis common to the projection objective and to the reception objective. 
     
     
       5. The system for detecting the posture of the mobile object according to  claim 1 , wherein the fixed device comprises a matrix of point emission sources, the said sources being turned on as a function of a position of the mobile object. 
     
     
       6. The system for detecting the posture of the mobile object according to  claim 1 , wherein the mobile object is a pilot helmet. 
     
     
       7. The system for detecting the posture of the mobile object according to  claim 1 , wherein the electro-optical fixed device is mounted at a known position and a known orientation on a pilot helmet. 
     
     
       8. The system for detecting the posture of the mobile object according to  claim 1 , wherein the mobile object is a weapon system comprising sighting means. 
     
     
       9. The system for detecting the posture of the mobile object according to  claim 8 , wherein the weapon system is a firearm.